Means and method of making leather



Patented May 24, 1932 UNITED STATES MEANS AND METHOD or: mn g ite nna'rnnn No Drawing.

This invention relates to certain new and useful improvements in means and method of making leather, the peculiarities of which will be hereinafter fully described and claimed.

The main objects of my invention are, first, to produce tight leather and/or plump solid leather; second, to provide means to attain said objects third, to provide a method of using said means to attain said objects; and fourth, to save the hair.

I have found by practical use of my process that I can effect a very material saving of time in the treatment of hides for producing leather, and obtain a strong plump and very tight leather, and also save the hair. To do I rea.tmem-as abefmfethis I soak the hides, and green flesh and resoak two hours in fresh water. 6% lime with 1%% concentrated sodium sulphide crystals of strength (or the equivalent) in water to make 15% strength solution, in three treatments in the paddle Wheel, using one-third of above mixture successively on the same hides two hours apart, to loosen the hair in 18 hours Without destroying it.

For example, to treat a batch of 5000 lbs. of hides in 1800 gallons of water, I take 6% of 5000 lbs. equals 300 lbs. of lime, and mix it in about 150 gallons of cold water.

Then I take 1%% of 5000 lbs. equals about 62 lbs. of concentrated sodium sulphide crystals of 60% strength, and dissolve it in about 25 gallons of boiling hot water making 15% solution. I pour this into the lime mixture and allow it to cool.

Then I take one-third of above lime and I sodium sulphide mixture and add it to the 1800 gallons of water on the 5000 lbs. of hides. These are stirred by paddles or otherwise agitated for 15 or 20 minutes and then are let stand until the end of two hours.

Then add another one-third of said mixture, agitate and let stand until the end of the second two hour period.

Then I add- Applieation filed November 3,= 1930. Seria1 No. 493,227.

Thenaddthe final third, of the above miX- ture, and agitate as above.

- Allow the batohto stand forisiiz hours.

Thenagitate 15 or 20 minutes and let stand for eight hours, making eighteen hours I treatment to loosenthehair.

To illustrate, after soaking, green fieshing asdr z sqakins. tor -W r v fresh Water asabovestated, begin the first two hour pe riodattsayy l; pm, by adding the first third of. aid; lime; and; sodium sulphide mixture and git te' 1 Two. later, atfip. m., add the second hird? f hs ime and d ili lp ture, and agitate. g g

Two, hours later, at,5 p. m., give the third Wa ts 11 91112 ,.1 .1 rimen agitate 920minstee an et st nd l? a -r making up the said 1 8 hours of treatment.

Dur ng h. t me l empe et i the bet hshq rli be. k pt at? 5 eg 0 grees Eah, to. obtain the. best, results.

Anrothet suitab Pr s tbiloosn t m y 96 u ed, bs bl fin h e to deliming or alkalining process described later;

fter. the 18 hours, take out the hides and unhair bythe usual process of machine or handz pe a isn-f .After unh airing put the hidesfback into a delimi -rig. oralkalining solution consisting .of substantially the following proportions of the ingredients named: 250% clear water, ss ium ulph d i Q- diu n hydroxide,.l.0% common salt.

1 Thehides are left in this alkalinesolution from four-to six hours. After this period Washthe hides for 20 minutes in. clear water.

Thensoalg the hides over night or abouteight hours, a 2% salt water solution;

Then bate the hides at least half an hour Wi h-1 01f T. 1% at 1 -0 Qmro r mintu-re of ammoniac and hardwood sawdust at about degrees F., and, neutralize or';

pickle in a solution consisting of: 0.5%

formic acid, 4l.0% salt, 0.25% wheat flour. Keep the hides in this solution for about 1 hour.

and unhairing, then alkalining four to six hours in a solution of substantially the follows ing proportions: 2.7% sodium sulphide, 2.5% lime, 0.5% sodium hydroxide and 4.0% common salt, dissolved in 250% clear water, then washing in clear water, then soaking in a salt water solution, hating, pickling, and then tanning, substantially as described.

In testimony whereof have affixed my signature.

FRANK WAVRA.

I do not limit myself to'the exact propor' I tions of the above named ingredients in thesolutions described, but give them as substantially the preferred proportions of means for carrying out my method of treating hides for producing leather of improved quality.

I claim:

1.. In the herein described treatment of hides for producing improved leather, the

- process of stirring into a batch of soaked hides a solution of substantially 6% lime and 1 4% concentrated sodium sulphide crystals of 60 strength, or equivalent in three installments of one-third each and two hoursiapart,

waiting six hours, agitating minutes, letting stand eight hours, taking out and unhairing, soaking in an alkalining solution, washing,soaking eight hours in a. salt solution,

'batmg, pickling, and then tanning, substan tially as described. I

2. A'composition of matterfor producing improved leather, the herein described alkalining solution consisting of sodium'sulphide,

lime, sodium hydroxide and common salt, dissolved in water. a 3 3. A com-positionof matter for producing improved leather, the herein described alkalining solution consisting of 2.7% sodium sulphide, 2.5%lime, 0. 5 sodium hydroxide and 4.0% common salt, dissolved in 250% clear water. i

4:. A composition of matter for producing improved leather, an alkalining process comprising soaking the hides in a solution of sodium sulphide, lime, sodium hydroxide and common salt, dissolved in water.

5. In the treatment of hides for producing improved leather, the herein described alkalining process comprising soaking thehides about one hour in a solution of substantially the following proportions: 2.7% sodium sulphide, 2.5% lime, 0.5% sodium hydroxide and 4.0% common salt, dissolved in 250% clear water, substantially as described.

6. In the treatment of hides for producing 5 improved leather, the herein described pr0cess comprlsln'g adding to the soaked hides a solution of lime and concentrated sodium sulphide, letting stand and agitating at'intervals: for 18' hours at 80 Fah. taking out. 

